Multiple choice

Directions: Fill in the blank with the most appropriate of the given options.

Not only _______ to determine the depth of the ocean floor, but it is also used to locate oil.

  1. we use seismology

  2. is seismology used

  3. seismology is used

  4. seismology blinds usage

  5. we used seismology

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The structure 'Not only... but also' requires inversion of the subject and verb in the first clause. 'Is seismology used' correctly follows this rule.